Standard Gestures

ABSTRACT

Systems, methods and computer readable media are disclosed for grouping complementary sets of standard gestures into gesture libraries. The gestures may be complementary in that they are frequently used together in a context or in that their parameters are interrelated. Where a parameter of a gesture is set with a first value, all other parameters of the gesture and of other gestures in the gesture package that depend on the first value may be set with their own value which is determined using the first value.

PRIORITY

The present application claims priority to provisional application61/148,884, titled “Standard Gestures,” filed Jan. 30, 2009, thecontents of which are incorporated herein in its entirety.

BACKGROUND OF THE INVENTION

Many computing applications such as computer games, multimediaapplications, office applications or the like use controls to allowusers to manipulate game characters or other aspects of an application.Typically such controls are input using, for example, controllers,remotes, keyboards, mice, or the like. Unfortunately, such controls canbe difficult to learn, thus creating a barrier between a user and suchgames and applications. Furthermore, such controls may be different thanactual game actions or other application actions for which the controlsare used. For example, a game control that causes a game character toswing a baseball bat may not correspond to an actual motion of swingingthe baseball bat.

SUMMARY OF THE INVENTION

Disclosed herein are systems and methods for receiving data reflectingskeletal movement of a user, and determining from that data whether theuser has performed one or more gestures. Packages of standard gesturesare disclosed from which application developers can incorporate gesturerecognition into their applications.

In an exemplary embodiment, a gesture library comprises a plurality ofgestures. Where these gestures are complementary with each other, theymay be grouped into gesture packages. These gesture packages are thenprovided to applications for use by a gesture recognizer engine. Anapplication may utilize one or more gesture packages.

The application may assign a value to a first parameter of a gesture,such as an arm velocity minimum threshold that must be reached for afootball throw gesture to be recognized. The recognizer engine sets thefirst parameter with the value, and also sets the value of any otherparameters of that gesture or any other gestures in the gesture packagethat are dependent upon the value of the first gesture. For instance,where the gesture package is a sports gesture package that includes thefootball throw gesture, the package may also include a curveballbaseball throw gesture and a fastball baseball throw gesture that areinterrelated with the football throw gesture. Where it has beendetermined that the curveball baseball throw gesture should have an armvelocity minimum threshold of 80% and the fastball baseball throwgesture should have an arm velocity minimum threshold of 90% of thefootball throw gesture, then those parameters may be set to 80% and 90%of the value, respectively.

It can be appreciated by one of skill in the art that one or morevarious aspects of the disclosure may include but are not limited tocircuitry and/or programming for effecting the herein-referenced aspectsof the present disclosure; the circuitry and/or programming can bevirtually any combination of hardware, software, and/or firmwareconfigured to effect the herein-referenced aspects depending upon thedesign choices of the system designer.

The foregoing is a summary and thus contains, by necessity,simplifications, generalizations and omissions of detail. Those skilledin the art will appreciate that the summary is illustrative only and isnot intended to be in any way limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The systems, methods, and computer readable media for gesture packagesof complementary gestures in accordance with this specification arefurther described with reference to the accompanying drawings in which:

FIGS. 1A and 1B illustrate an example embodiment of a targetrecognition, analysis, and tracking system with a user playing a game.

FIG. 2 illustrates an example embodiment of a capture device that may beused in a target recognition, analysis, and tracking system.

FIG. 3A illustrates an example embodiment of a computing environmentthat may be used to interpret one or more gestures in a targetrecognition, analysis, and tracking system.

FIG. 3B illustrates another example embodiment of a computingenvironment that may be used to interpret one or more gestures in atarget recognition, analysis, and tracking system.

FIG. 4A illustrates a skeletal mapping of a user that has been generatedfrom the target recognition, analysis, and tracking system of FIG. 2.

FIG. 4B illustrates further details of the gesture recognizerarchitecture shown in FIG. 2.

FIG. 5 illustrates how gesture filters may be stacked to create morecomplex gesture filters.

FIG. 6 illustrates an example gesture that a user 502 may make to signalfor a “fair catch” in football video game.

FIG. 7 illustrates the example “fair catch” gesture of FIG. 5 as eachframe of image data has been parsed to produce a skeletal map of theuser.

FIG. 8 illustrates how generic gestures from a gesture library aregrouped into genre packages of complementary gestures for a particulartask.

FIG. 9 illustrates exemplary operational procedures for tuningcomplementary gestures in a gesture package when an application providesa value for one parameter of one gesture.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

As will be described herein, a user may control an application executingon a computing environment such as a game console, a computer, or thelike by performing one or more gestures. According to one embodiment,the gestures may be received by, for example, a capture device. Forexample, the capture device may capture a depth image of a scene. In oneembodiment, the capture device may determine whether one or more targetsor objects in the scene corresponds to a human target such as the user.To determine whether a target or object in the scene corresponds a humantarget, each of the targets may be flood filled and compared to apattern of a human body model. Each target or object that matches thehuman body model may then be scanned to generate a skeletal modelassociated therewith. The skeletal model may then be provided to thecomputing environment such that the computing environment may track theskeletal model, render an avatar associated with the skeletal model, andmay determine which controls to perform in an application executing onthe computer environment based on, for example, gestures of the userthat have been recognized from the skeletal model. A gesture recognizerengine, the architecture of which is described more fully below, is usedto determine when a particular gesture has been made by the user.

FIGS. 1A and 1B illustrate an example embodiment of a configuration of atarget recognition, analysis, and tracking system 10 with a user 18playing a boxing game. In an example embodiment, the target recognition,analysis, and tracking system 10 may be used to recognize, analyze,and/or track a human target such as the user 18.

As shown in FIG. 1A, the target recognition, analysis, and trackingsystem 10 may include a computing environment 12. The computingenvironment 12 may be a computer, a gaming system or console, or thelike. According to an example embodiment, the computing environment 12may include hardware components and/or software components such that thecomputing environment 12 may be used to execute applications such asgaming applications, non-gaming applications, or the like.

As shown in FIG. 1A, the target recognition, analysis, and trackingsystem 10 may further include a capture device 20. The capture device 20may be, for example, a camera that may be used to visually monitor oneor more users, such as the user 18, such that gestures performed by theone or more users may be captured, analyzed, and tracked to perform oneor more controls or actions within an application, as will be describedin more detail below.

According to one embodiment, the target recognition, analysis, andtracking system 10 may be connected to an audiovisual device 16 such asa television, a monitor, a high-definition television (HDTV), or thelike that may provide game or application visuals and/or audio to a usersuch as the user 18. For example, the computing environment 12 mayinclude a video adapter such as a graphics card and/or an audio adaptersuch as a sound card that may provide audiovisual signals associatedwith the game application, non-game application, or the like. Theaudiovisual device 16 may receive the audiovisual signals from thecomputing environment 12 and may then output the game or applicationvisuals and/or audio associated with the audiovisual signals to the user18. According to one embodiment, the audiovisual device 16 may beconnected to the computing environment 12 via, for example, an S-Videocable, a coaxial cable, an HDMI cable, a DVI cable, a VGA cable, or thelike.

As shown in FIGS. 1A and 1B, the target recognition, analysis, andtracking system 10 may be used to recognize, analyze, and/or track ahuman target such as the user 18. For example, the user 18 may betracked using the capture device 20 such that the movements of user 18may be interpreted as controls that may be used to affect theapplication being executed by computer environment 12. Thus, accordingto one embodiment, the user 18 may move his or her body to control theapplication.

As shown in FIGS. 1A and 1B, in an example embodiment, the applicationexecuting on the computing environment 12 may be a boxing game that theuser 18 may be playing. For example, the computing environment 12 mayuse the audiovisual device 16 to provide a visual representation of aboxing opponent 22 to the user 18. The computing environment 12 may alsouse the audiovisual device 16 to provide a visual representation of aplayer avatar 24 that the user 18 may control with his or her movements.For example, as shown in FIG. 1B, the user 18 may throw a punch inphysical space to cause the player avatar 24 to throw a punch in gamespace. Thus, according to an example embodiment, the computerenvironment 12 and the capture device 20 of the target recognition,analysis, and tracking system 10 may be used to recognize and analyzethe punch of the user 18 in physical space such that the punch may beinterpreted as a game control of the player avatar 24 in game space.

Other movements by the user 18 may also be interpreted as other controlsor actions, such as controls to bob, weave, shuffle, block, jab, orthrow a variety of different power punches. Furthermore, some movementsmay be interpreted as controls that may correspond to actions other thancontrolling the player avatar 24. For example, the player may usemovements to end, pause, or save a game, select a level, view highscores, communicate with a friend, etc.

In example embodiments, the human target such as the user 18 may have anobject. In such embodiments, the user of an electronic game may beholding the object such that the motions of the player and the objectmay be used to adjust and/or control parameters of the game. Forexample, the motion of a player holding a racket may be tracked andutilized for controlling an on-screen racket in an electronic sportsgame. In another example embodiment, the motion of a player holding anobject may be tracked and utilized for controlling an on-screen weaponin an electronic combat game.

According to other example embodiments, the target recognition,analysis, and tracking system 10 may further be used to interpret targetmovements as operating system and/or application controls that areoutside the realm of games. For example, virtually any controllableaspect of an operating system and/or application may be controlled bymovements of the target such as the user 18.

FIG. 2 illustrates an example embodiment of the capture device 20 thatmay be used in the target recognition, analysis, and tracking system 10.According to an example embodiment, the capture device 20 may beconfigured to capture video with depth information including a depthimage that may include depth values via any suitable techniqueincluding, for example, time-of-flight, structured light, stereo image,or the like. According to one embodiment, the capture device 20 mayorganize the calculated depth information into “Z layers,” or layersthat may be perpendicular to a Z axis extending from the depth cameraalong its line of sight.

As shown in FIG. 2, the capture device 20 may include an image cameracomponent 22. According to an example embodiment, the image cameracomponent 22 may be a depth camera that may capture the depth image of ascene. The depth image may include a two-dimensional (2-D) pixel area ofthe captured scene where each pixel in the 2-D pixel area may representa length in, for example, centimeters, millimeters, or the like of anobject in the captured scene from the camera.

As shown in FIG. 2, according to an example embodiment, the image cameracomponent 22 may include an IR light component 24, a three-dimensional(3-D) camera 26, and an RGB camera 28 that may be used to capture thedepth image of a scene. For example, in time-of-flight analysis, the IRlight component 24 of the capture device 20 may emit an infrared lightonto the scene and may then use sensors (not shown) to detect thebackscattered light from the surface of one or more targets and objectsin the scene using, for example, the 3-D camera 26 and/or the RGB camera28. In some embodiments, pulsed infrared light may be used such that thetime between an outgoing light pulse and a corresponding incoming lightpulse may be measured and used to determine a physical distance from thecapture device 20 to a particular location on the targets or objects inthe scene. Additionally, in other example embodiments, the phase of theoutgoing light wave may be compared to the phase of the incoming lightwave to determine a phase shift. The phase shift may then be used todetermine a physical distance from the capture device to a particularlocation on the targets or objects.

According to another example embodiment, time-of-flight analysis may beused to indirectly determine a physical distance from the capture device20 to a particular location on the targets or objects by analyzing theintensity of the reflected beam of light over time via varioustechniques including, for example, shuttered light pulse imaging.

In another example embodiment, the capture device 20 may use astructured light to capture depth information. In such an analysis,patterned light (i.e., light displayed as a known pattern such as gridpattern or a stripe pattern) may be projected onto the scene via, forexample, the IR light component 24. Upon striking the surface of one ormore targets or objects in the scene, the pattern may become deformed inresponse. Such a deformation of the pattern may be captured by, forexample, the 3-D camera 26 and/or the RGB camera 28 and may then beanalyzed to determine a physical distance from the capture device to aparticular location on the targets or objects.

According to another embodiment, the capture device 20 may include twoor more physically separated cameras that may view a scene fromdifferent angles, to obtain visual stereo data that may be resolved togenerate depth information

The capture device 20 may further include a microphone 30. Themicrophone 30 may include a transducer or sensor that may receive andconvert sound into an electrical signal. According to one embodiment,the microphone 30 may be used to reduce feedback between the capturedevice 20 and the computing environment 12 in the target recognition,analysis, and tracking system 10. Additionally, the microphone 30 may beused to receive audio signals that may also be provided by the user tocontrol applications such as game applications, non-game applications,or the like that may be executed by the computing environment 12.

In an example embodiment, the capture device 20 may further include aprocessor 32 that may be in operative communication with the imagecamera component 22. The processor 32 may include a standardizedprocessor, a specialized processor, a microprocessor, or the like thatmay execute instructions that may include instructions for receiving thedepth image, determining whether a suitable target may be included inthe depth image, converting the suitable target into a skeletalrepresentation or model of the target, or any other suitableinstruction.

The capture device 20 may further include a memory component 34 that maystore the instructions that may be executed by the processor 32, imagesor frames of images captured by the 3-D camera or RGB camera, or anyother suitable information, images, or the like. According to an exampleembodiment, the memory component 34 may include random access memory(RAM), read only memory (ROM), cache, Flash memory, a hard disk, or anyother suitable storage component. As shown in FIG. 2, in one embodiment,the memory component 34 may be a separate component in communicationwith the image capture component 22 and the processor 32. According toanother embodiment, the memory component 34 may be integrated into theprocessor 32 and/or the image capture component 22.

As shown in FIG. 2, the capture device 20 may be in communication withthe computing environment 12 via a communication link 36. Thecommunication link 36 may be a wired connection including, for example,a USB connection, a Firewire connection, an Ethernet cable connection,or the like and/or a wireless connection such as a wireless 802.11b, g,a, or n connection. According to one embodiment, the computingenvironment 12 may provide a clock to the capture device 20 that may beused to determine when to capture, for example, a scene via thecommunication link 36.

Additionally, the capture device 20 may provide the depth informationand images captured by, for example, the 3-D camera 26 and/or the RGBcamera 28, and a skeletal model that may be generated by the capturedevice 20 to the computing environment 12 via the communication link 36.The computing environment 12 may then use the skeletal model, depthinformation, and captured images to, for example, recognize usergestures and in response control an application such as a game or wordprocessor. For example, as shown, in FIG. 2, the computing environment12 may include a gestures recognizer engine 190. The gestures recognizerengine 190 may include a collection of gesture filters, each comprisinginformation concerning a gesture that may be performed by the skeletalmodel (as the user moves). The data captured by the cameras 26, 28 anddevice 20 in the form of the skeletal model and movements associatedwith it may be compared to the gesture filters in the gesture recognizerengine 190 to identify when a user (as represented by the skeletalmodel) has performed one or more gestures. Those gestures may beassociated with various controls of an application. Thus, the computingenvironment 12 may use the gesture recognizer engine 190 to interpretmovements of the skeletal model and to control an application based onthe movements.

FIG. 3A illustrates an example embodiment of a computing environmentthat may be used to interpret one or more gestures in a targetrecognition, analysis, and tracking system. The computing environmentsuch as the computing environment 12 described above with respect toFIGS. 1A-2 may be a multimedia console 100, such as a gaming console. Asshown in FIG. 3A, the multimedia console 100 has a central processingunit (CPU) 101 having a level 1 cache 102, a level 2 cache 104, and aflash ROM (Read Only Memory) 106. The level 1 cache 102 and a level 2cache 104 temporarily store data and hence reduce the number of memoryaccess cycles, thereby improving processing speed and throughput. TheCPU 101 may be provided having more than one core, and thus, additionallevel 1 and level 2 caches 102 and 104. The flash ROM 106 may storeexecutable code that is loaded during an initial phase of a boot processwhen the multimedia console 100 is powered ON.

A graphics processing unit (GPU) 108 and a video encoder/video codec(coder/decoder) 114 form a video processing pipeline for high speed andhigh resolution graphics processing. Data is carried from the graphicsprocessing unit 108 to the video encoder/video codec 114 via a bus. Thevideo processing pipeline outputs data to an A/V (audio/video) port 140for transmission to a television or other display. A memory controller110 is connected to the GPU 108 to facilitate processor access tovarious types of memory 112, such as, but not limited to, a RAM (RandomAccess Memory).

The multimedia console 100 includes an I/O controller 120, a systemmanagement controller 122, an audio processing unit 123, a networkinterface controller 124, a first USB host controller 126, a second USBcontroller 128 and a front panel I/O subassembly 130 that are preferablyimplemented on a module 118. The USB controllers 126 and 128 serve ashosts for peripheral controllers 142(1)-142(2), a wireless adapter 148,and an external memory device 146 (e.g., flash memory, external CD/DVDROM drive, removable media, etc.). The network interface 124 and/orwireless adapter 148 provide access to a network (e.g., the Internet,home network, etc.) and may be any of a wide variety of various wired orwireless adapter components including an Ethernet card, a modem, aBluetooth module, a cable modem, and the like.

System memory 143 is provided to store application data that is loadedduring the boot process. A media drive 144 is provided and may comprisea DVD/CD drive, hard drive, or other removable media drive, etc. Themedia drive 144 may be internal or external to the multimedia console100. Application data may be accessed via the media drive 144 forexecution, playback, etc. by the multimedia console 100. The media drive144 is connected to the I/O controller 120 via a bus, such as a SerialATA bus or other high speed connection (e.g., IEEE 1394).

The system management controller 122 provides a variety of servicefunctions related to assuring availability of the multimedia console100. The audio processing unit 123 and an audio codec 132 form acorresponding audio processing pipeline with high fidelity and stereoprocessing. Audio data is carried between the audio processing unit 123and the audio codec 132 via a communication link. The audio processingpipeline outputs data to the A/V port 140 for reproduction by anexternal audio player or device having audio capabilities.

The front panel I/O subassembly 130 supports the functionality of thepower button 150 and the eject button 152, as well as any LEDs (lightemitting diodes) or other indicators exposed on the outer surface of themultimedia console 100. A system power supply module 136 provides powerto the components of the multimedia console 100. A fan 138 cools thecircuitry within the multimedia console 100.

The CPU 101, GPU 108, memory controller 110, and various othercomponents within the multimedia console 100 are interconnected via oneor more buses, including serial and parallel buses, a memory bus, aperipheral bus, and a processor or local bus using any of a variety ofbus architectures. By way of example, such architectures can include aPeripheral Component Interconnects (PCI) bus, PCI-Express bus, etc.

When the multimedia console 100 is powered ON, application data may beloaded from the system memory 143 into memory 112 and/or caches 102, 104and executed on the CPU 101. The application may present a graphicaluser interface that provides a consistent user experience whennavigating to different media types available on the multimedia console100. In operation, applications and/or other media contained within themedia drive 144 may be launched or played from the media drive 144 toprovide additional functionalities to the multimedia console 100.

The multimedia console 100 may be operated as a standalone system bysimply connecting the system to a television or other display. In thisstandalone mode, the multimedia console 100 allows one or more users tointeract with the system, watch movies, or listen to music. However,with the integration of broadband connectivity made available throughthe network interface 124 or the wireless adapter 148, the multimediaconsole 100 may further be operated as a participant in a larger networkcommunity.

When the multimedia console 100 is powered ON, a set amount of hardwareresources are reserved for system use by the multimedia consoleoperating system. These resources may include a reservation of memory(e.g., 16 MB), CPU and GPU cycles (e.g., 5%), networking bandwidth(e.g., 8 kbs), etc. Because these resources are reserved at system boottime, the reserved resources do not exist from the application's view.

In particular, the memory reservation preferably is large enough tocontain the launch kernel, concurrent system applications and drivers.The CPU reservation is preferably constant such that if the reserved CPUusage is not used by the system applications, an idle thread willconsume any unused cycles.

With regard to the GPU reservation, lightweight messages generated bythe system applications (e.g., popups) are displayed by using a GPUinterrupt to schedule code to render popup into an overlay. The amountof memory required for an overlay depends on the overlay area size andthe overlay preferably scales with screen resolution. Where a full userinterface is used by the concurrent system application, it is preferableto use a resolution independent of application resolution. A scaler maybe used to set this resolution such that the need to change frequencyand cause a TV resynch is eliminated.

After the multimedia console 100 boots and system resources arereserved, concurrent system applications execute to provide systemfunctionalities. The system functionalities are encapsulated in a set ofsystem applications that execute within the reserved system resourcesdescribed above. The operating system kernel identifies threads that aresystem application threads versus gaming application threads. The systemapplications are preferably scheduled to run on the CPU 101 atpredetermined times and intervals in order to provide a consistentsystem resource view to the application. The scheduling is to minimizecache disruption for the gaming application running on the console.

When a concurrent system application requires audio, audio processing isscheduled asynchronously to the gaming application due to timesensitivity. A multimedia console application manager (described below)controls the gaming application audio level (e.g., mute, attenuate) whensystem applications are active.

Input devices (e.g., controllers 142(1) and 142(2)) are shared by gamingapplications and system applications. The input devices are not reservedresources, but are to be switched between system applications and thegaming application such that each will have a focus of the device. Theapplication manager preferably controls the switching of input stream,without knowledge the gaming application's knowledge and a drivermaintains state information regarding focus switches. The cameras 26, 28and capture device 20 may define additional input devices for theconsole 100.

FIG. 3B illustrates another example embodiment of a computingenvironment 220 that may be the computing environment 12 shown in FIGS.1A-2 used to interpret one or more gestures in a target recognition,analysis, and tracking system. The computing system environment 220 isonly one example of a suitable computing environment and is not intendedto suggest any limitation as to the scope of use or functionality of thepresently disclosed subject matter. Neither should the computingenvironment 220 be interpreted as having any dependency or requirementrelating to any one or combination of components illustrated in theexemplary operating environment 220. In some embodiments the variousdepicted computing elements may include circuitry configured toinstantiate specific aspects of the present disclosure. For example, theterm circuitry used in the disclosure can include specialized hardwarecomponents configured to perform function(s) by firmware or switches. Inother examples embodiments the term circuitry can include a generalpurpose processing unit, memory, etc., configured by softwareinstructions that embody logic operable to perform function(s). Inexample embodiments where circuitry includes a combination of hardwareand software, an implementer may write source code embodying logic andthe source code can be compiled into machine readable code that can beprocessed by the general purpose processing unit. Since one skilled inthe art can appreciate that the state of the art has evolved to a pointwhere there is little difference between hardware, software, or acombination of hardware/software, the selection of hardware versussoftware to effectuate specific functions is a design choice left to animplementer. More specifically, one of skill in the art can appreciatethat a software process can be transformed into an equivalent hardwarestructure, and a hardware structure can itself be transformed into anequivalent software process. Thus, the selection of a hardwareimplementation versus a software implementation is one of design choiceand left to the implementer.

In FIG. 3B, the computing environment 220 comprises a computer 241,which typically includes a variety of computer readable media. Computerreadable media can be any available media that can be accessed bycomputer 241 and includes both volatile and nonvolatile media, removableand non-removable media. The system memory 222 includes computer storagemedia in the form of volatile and/or nonvolatile memory such as readonly memory (ROM) 223 and random access memory (RAM) 260. A basicinput/output system 224 (BIOS), containing the basic routines that helpto transfer information between elements within computer 241, such asduring start-up, is typically stored in ROM 223. RAM 260 typicallycontains data and/or program modules that are immediately accessible toand/or presently being operated on by processing unit 259. By way ofexample, and not limitation, FIG. 3B illustrates operating system 225,application programs 226, other program modules 227, and program data228.

The computer 241 may also include other removable/non-removable,volatile/nonvolatile computer storage media. By way of example only,FIG. 3B illustrates a hard disk drive 238 that reads from or writes tonon-removable, nonvolatile magnetic media, a magnetic disk drive 239that reads from or writes to a removable, nonvolatile magnetic disk 254,and an optical disk drive 240 that reads from or writes to a removable,nonvolatile optical disk 253 such as a CD ROM or other optical media.Other removable/non-removable, volatile/nonvolatile computer storagemedia that can be used in the exemplary operating environment include,but are not limited to, magnetic tape cassettes, flash memory cards,digital versatile disks, digital video tape, solid state RAM, solidstate ROM, and the like. The hard disk drive 238 is typically connectedto the system bus 221 through a non-removable memory interface such asinterface 234, and magnetic disk drive 239 and optical disk drive 240are typically connected to the system bus 221 by a removable memoryinterface, such as interface 235.

The drives and their associated computer storage media discussed aboveand illustrated in FIG. 3B, provide storage of computer readableinstructions, data structures, program modules and other data for thecomputer 241. In FIG. 3B, for example, hard disk drive 238 isillustrated as storing operating system 258, application programs 257,other program modules 256, and program data 255. Note that thesecomponents can either be the same as or different from operating system225, application programs 226, other program modules 227, and programdata 228. Operating system 258, application programs 257, other programmodules 256, and program data 255 are given different numbers here toillustrate that, at a minimum, they are different copies. A user mayenter commands and information into the computer 241 through inputdevices such as a keyboard 251 and pointing device 252, commonlyreferred to as a mouse, trackball or touch pad. Other input devices (notshown) may include a microphone, joystick, game pad, satellite dish,scanner, or the like. These and other input devices are often connectedto the processing unit 259 through a user input interface 236 that iscoupled to the system bus, but may be connected by other interface andbus structures, such as a parallel port, game port or a universal serialbus (USB). The cameras 26, 28 and capture device 20 may defineadditional input devices for the console 100. A monitor 242 or othertype of display device is also connected to the system bus 221 via aninterface, such as a video interface 232. In addition to the monitor,computers may also include other peripheral output devices such asspeakers 244 and printer 243, which may be connected through a outputperipheral interface 233.

The computer 241 may operate in a networked environment using logicalconnections to one or more remote computers, such as a remote computer246. The remote computer 246 may be a personal computer, a server, arouter, a network PC, a peer device or other common network node, andtypically includes many or all of the elements described above relativeto the computer 241, although only a memory storage device 247 has beenillustrated in FIG. 3B. The logical connections depicted in FIG. 3Binclude a local area network (LAN) 245 and a wide area network (WAN)249, but may also include other networks. Such networking environmentsare commonplace in offices, enterprise-wide computer networks, intranetsand the Internet.

When used in a LAN networking environment, the computer 241 is connectedto the LAN 245 through a network interface or adapter 237. When used ina WAN networking environment, the computer 241 typically includes amodem 250 or other means for establishing communications over the WAN249, such as the Internet. The modem 250, which may be internal orexternal, may be connected to the system bus 221 via the user inputinterface 236, or other appropriate mechanism. In a networkedenvironment, program modules depicted relative to the computer 241, orportions thereof, may be stored in the remote memory storage device. Byway of example, and not limitation, FIG. 3B illustrates remoteapplication programs 248 as residing on memory device 247. It will beappreciated that the network connections shown are exemplary and othermeans of establishing a communications link between the computers may beused.

FIG. 4A depicts an example skeletal mapping of a user that may begenerated from the capture device 20. In this embodiment, a variety ofjoints and bones are identified: each hand 302, each forearm 304, eachelbow 306, each bicep 308, each shoulder 310, each hip 312, each thigh314, each knee 316, each foreleg 318, each foot 320, the head 322, thetorso 324, the top 326 and bottom 328 of the spine, and the waist 330.Where more points are tracked, additional features may be identified,such as the bones and joints of the fingers or toes, or individualfeatures of the face, such as the nose and eyes.

Through moving his body, a user may create gestures. A gesture comprisesa motion or pose by a user that may be captured as image data and parsedfor meaning. A gesture may be dynamic, comprising a motion, such asmimicking throwing a ball. A gesture may be a static pose, such asholding one's crossed forearms 304 in front of his torso 324. A gesturemay also incorporate props, such as by swinging a mock sword. A gesturemay comprise more than one body part, such as clapping the hands 302together, or a subtler motion, such as pursing one's lips.

Gestures may be used for input in a general computing context. Forinstance, various motions of the hands 302 or other body parts maycorrespond to common system wide tasks such as navigate up or down in ahierarchical list, open a file, close a file, and save a file. Gesturesmay also be used in a video-game-specific context, depending on thegame. For instance, with a driving game, various motions of the hands302 and feet 320 may correspond to steering a vehicle in a direction,shifting gears, accelerating, and breaking.

A user may generate a gesture that corresponds to walking or running, bywalking or running in place himself. The user may alternately lift anddrop each leg 312-320 to mimic walking without moving. The system mayparse this gesture by analyzing each hip 312 and each thigh 314. A stepmay be recognized when one hip-thigh angle (as measured relative to avertical line, wherein a standing leg has a hip-thigh angle of 0°, and aforward horizontally extended leg has a hip-thigh angle of 90°) exceedsa certain threshold relative to the other thigh. A walk or run may berecognized after some number of consecutive steps by alternating legs.The time between the two most recent steps may be thought of as aperiod. After some number of periods where that threshold angle is notmet, the system may determine that the walk or running gesture hasceased.

Given a “walk or run” gesture, an application may set values forapplication-determined parameters associated with this gesture. Theseparameters may include the above threshold angle, the number of stepsrequired to initiate a walk or run gesture, a number of periods where nostep occurs to end the gesture, and a threshold period that determineswhether the gesture is a walk or a run. A fast period may correspond toa run, as the user will be moving his legs quickly, and a slower periodmay correspond to a walk.

A gesture may be associated with a set of default parameters at firstthat the application may override with its own parameters. In thisscenario, an application is not forced to provide parameters, but mayinstead use a set of default parameters that allow the gesture to berecognized in the absence of application-defined parameters.

There are a variety of outputs that may be associated with the gesture.There may be a baseline “yes or no” as to whether a gesture isoccurring. There also may be a confidence level, which corresponds tothe likelihood that the user's tracked movement corresponds to thegesture. This could be a linear scale that ranges over floating pointnumbers between 0 and 1, inclusive. Wherein an application receivingthis gesture information cannot accept false-positives as input, it mayuse only those recognized gestures that have a high confidence level,such as at least 0.95. Where an application must recognize everyinstance of the gesture, even at the cost of false-positives, it may usegestures that have at least a much lower confidence level, such as thosemerely greater than 0.2. The gesture may have an output for the timebetween the two most recent steps, and where only a first step has beenregistered, this may be set to a reserved value, such as −1 (since thetime between any two steps must be positive). The gesture may also havean output for the highest thigh angle reached during the most recentstep.

Another exemplary gesture is a “heel lift jump.” In this, a user maycreate the gesture by raising his heels off the ground, but keeping histoes planted. Alternatively, the user may jump into the air where hisfeet 320 leave the ground entirely. The system may parse the skeletonfor this gesture by analyzing the angle relation of the shoulders 310,hips 312 and knees 316 to see if they are in a position of alignmentequal to standing up straight. Then these points and upper 326 and lower328 spine points may be monitored for any upward acceleration. Asufficient combination of acceleration may trigger a jump gesture.

Given this “heel lift jump” gesture, an application may set values forapplication-determined parameters associated with this gesture. Theparameters may include the above acceleration threshold, whichdetermines how fast some combination of the user's shoulders 310, hips312 and knees 316 must move upward to trigger the gesture, as well as amaximum angle of alignment between the shoulders 310, hips 312 and knees316 at which a jump may still be triggered.

The outputs may comprise a confidence level, as well as the user's bodyangle at the time of the jump.

Setting parameters for a gesture based on the particulars of theapplication that will receive the gesture is important in accuratelyidentifying gestures. Properly identifying gestures and the intent of auser greatly helps in creating a positive user experience. Where agesture recognizer system is too sensitive, and even a slight forwardmotion of the hand 302 is interpreted as a throw, the user may becomefrustrated because gestures are being recognized where he has no intentto make a gesture, and thus, he lacks control over the system. Where agesture recognizer system is not sensitive enough, the system may notrecognize conscious attempts by the user to make a throwing gesture,frustrating him in a similar manner. At either end of the sensitivityspectrum, the user becomes frustrated because he cannot properly provideinput to the system.

Another parameter to a gesture may be a distance moved. Where a user'sgestures control the actions of an avatar in a virtual environment, thatavatar may be arm's length from a ball. If the user wishes to interactwith the ball and grab it, this may require the user to extend his arm302-310 to full length while making the grab gesture. In this situation,a similar grab gesture where the user only partially extends his arm302-310 may not achieve the result of interacting with the ball.

A gesture or a portion thereof may have as a parameter a volume of spacein which it must occur. This volume of space may typically be expressedin relation to the body where a gesture comprises body movement. Forinstance, a football throwing gesture for a right-handed user may berecognized only in the volume of space no lower than the right shoulder310 a, and on the same side of the head 322 as the throwing arm 302a-310 a. It may not be necessary to define all bounds of a volume, suchas with this throwing gesture, where an outer bound away from the bodyis left undefined, and the volume extends out indefinitely, or to theedge of scene that is being monitored.

FIG. 4B provides further details of one exemplary embodiment of thegesture recognizer engine 190 of FIG. 2. As shown, the gesturerecognizer engine 190 may comprise at least one filter 418 to determinea gesture or gestures. A filter 418 comprises information defining agesture 426 (hereinafter referred to as a “gesture”), and may alsocomprise parameters 428, or metadata, for that gesture. For instance, athrow, which comprises motion of one of the hands from behind the rearof the body to past the front of the body, may be implemented as agesture 426 comprising information representing the movement of one ofthe hands of the user from behind the rear of the body to past the frontof the body, as that movement would be captured by the depth camera.Parameters 428 may then be set for that gesture 426. Where the gesture426 is a throw, a parameter 428 may be a threshold velocity that thehand has to reach, a distance the hand must travel (either absolute, orrelative to the size of the user as a whole), and a confidence rating bythe recognizer engine that the gesture occurred. These parameters 428for the gesture 426 may vary between applications, between contexts of asingle application, or within one context of one application over time.

Filters may be modular or interchangeable. In an embodiment, a filterhas a number of inputs, each of those inputs having a type, and a numberof outputs, each of those outputs having a type. In this situation, afirst filter may be replaced with a second filter that has the samenumber and types of inputs and outputs as the first filter withoutaltering any other aspect of the recognizer engine architecture. Forinstance, there may be a first filter for driving that takes as inputskeletal data and outputs a confidence that the gesture associated withthe filter is occurring and an angle of steering. Where one wishes tosubstitute this first driving filter with a second drivingfilter—perhaps because the second driving filter is more efficient andrequires fewer processing resources—one may do so by simply replacingthe first filter with the second filter so long as the second filter hasthose same inputs and outputs—one input of skeletal data type, and twooutputs of confidence type and angle type.

A filter need not have a parameter. For instance, a “user height” filterthat returns the user's height may not allow for any parameters that maybe tuned. An alternate “user height” filter may have tunableparameters—such as to whether to account for a user's footwear,hairstyle, headwear and posture in determining the user's height.

Inputs to a filter may comprise things such as joint data about a user'sjoint position, like angles formed by the bones that meet at the joint,RGB color data from the scene, and the rate of change of an aspect ofthe user. Outputs from a filter may comprise things such as theconfidence that a given gesture is being made, the speed at which agesture motion is made, and a time at which a gesture motion is made.

A context may be a cultural context, and it may be an environmentalcontext. A cultural context refers to the culture of a user using asystem. Different cultures may use similar gestures to impart markedlydifferent meanings. For instance, an American user who wishes to tellanother user to “look” or “use his eyes” may put his index finger on hishead close to the distal side of his eye. However, to an Italian user,this gesture may be interpreted as a reference to the mafia.

Similarly, there may be different contexts among different environmentsof a single application. Take a first-person shooter game that involvesoperating a motor vehicle. While the user is on foot, making a firstwith the fingers towards the ground and extending the first in front andaway from the body may represent a punching gesture. While the user isin the driving context, that same motion may represent a “gear shifting”gesture. There may also be one or more menu environments, where the usercan save his game, select among his character's equipment or performsimilar actions that do not comprise direct game-play. In thatenvironment, this same gesture may have a third meaning, such as toselect something or to advance to another screen.

The gesture recognizer engine 190 may have a base recognizer engine 416that provides functionality to a gesture filter 418. In an embodiment,the functionality that the recognizer engine 416 implements includes aninput-over-time archive that tracks recognized gestures and other input,a Hidden Markov Model implementation (where the modeled system isassumed to be a Markov process—one where a present state encapsulatesany past state information necessary to determine a future state, so noother past state information must be maintained for this purpose—withunknown parameters, and hidden parameters are determined from theobservable data), as well as other functionality required to solveparticular instances of gesture recognition.

Filters 418 are loaded and implemented on top of the base recognizerengine 416 and can utilize services provided by the engine 416 to allfilters 418. In an embodiment, the base recognizer engine 416 processesreceived data to determine whether it meets the requirements of anyfilter 418. Since these provided services, such as parsing the input,are provided once by the base recognizer engine 416 rather than by eachfilter 418, such a service need only be processed once in a period oftime as opposed to once per filter 418 for that period, so theprocessing required to determine gestures is reduced.

An application may use the filters 418 provided by the recognizer engine190, or it may provide its own filter 418, which plugs in to the baserecognizer engine 416. In an embodiment, all filters 418 have a commoninterface to enable this plug-in characteristic. Further, all filters418 may utilize parameters 428, so a single gesture tool as describedbelow may be used to debug and tune the entire filter system 418.

These parameters 428 may be tuned for an application or a context of anapplication by a gesture tool 420. In an embodiment, the gesture tool420 comprises a plurality of sliders 422, each slider 422 correspondingto a parameter 428, as well as a pectoral representation of a body 424.As a parameter 428 is adjusted with a corresponding slider 422, the body424 may demonstrate both actions that would be recognized as the gesturewith those parameters 428 and actions that would not be recognized asthe gesture with those parameters 428, identified as such. Thisvisualization of the parameters 428 of gestures provides an effectivemeans to both debug and fine tune a gesture.

FIG. 5 depicts more complex gestures or filters 418 created from stackedgestures or filters 418. Gestures can stack on each other, and a stackedfilter may then be thought of as a filter comprising a plurality ofother filters. That is, more than one gesture may be expressed by a userat a single time. For instance, rather than disallowing any input but athrow when a throwing gesture is made, or requiring that a user remainmotionless save for the components of the gesture (e.g. stand stillwhile making a throwing gesture that involves only one arm). Wheregestures stack, a user may make a jumping gesture and a throwing gesturesimultaneously, and both of these gestures will be recognized by thegesture engine.

FIG. 5A depicts a simple gesture filter 418 according to the stackingparadigm. The IFilter filter 502 is a basic filter 418 that may be usedin every gesture filter. IFilter 502 takes user position data 504 andoutputs a confidence level 506 that a gesture has occurred. It alsofeeds that position data 504 into a SteeringWheel filter 508 that takesit as an input and outputs an angle to which the user is steering (e.g.40 degrees to the right of the user's current bearing) 510.

FIG. 5B depicts a more complex gesture that stacks filters 418 onto thegesture filter of FIG. 5A. In addition to IFilter 502 and SteeringWheel508, there is an ITracking filter 512 that receives position data 504from IFilter 502 and outputs the amount of progress the user has madethrough a gesture 514. ITracking 512 also feeds position data 504 toGreaseLightning 514 and EBrake 516, which are filters 418 regardingother gestures that may be made in operating a vehicle, such as usingthe emergency brake.

There exist other embodiments for stacking gestures. It an embodiment,position data 504 is passed directly to all filters of the stackedgesture, rather than through IFilter 502, and a component of therecognizer engine determines how each filter interoperates. For example,with a jump filter and a throw filter, each may be recognizedindependently when no other user action is occurring, but this componentwould recognize that a jump and some user input that may be a throw areoccurring simultaneously based on the respective output from eachfilter. This component may then interpret the throw filter lessrigorously (for instance, by expanding the acceptable range of values tosatisfy a parameter), and based on that the “some input that may be athrow” may be recognized as a throw.

FIG. 6 depicts an example gesture that a user 602 may make to signal fora “fair catch” in a football video game. These figures depict the userat points in time, with FIG. 6A being the first point in time, and FIG.6E being the last point in time. Each of these figures may correspond toa snapshot or frame of image data as captured by a depth camera 402,though not necessarily consecutive frames of image data, as the depthcamera 402 may be able to capture frames more rapidly than the user maycover the distance. For instance, this gesture may occur over a periodof 3 seconds, and where a depth camera captures data at 40 frames persecond, it would capture 60 frames of image data while the user 602 madethis fair catch gesture.

In FIG. 6A, the user 602 begins with his arms 604 down at his sides. Hethen raises them up and above his shoulders as depicted in FIG. 6B andthen further up, to the approximate level of his head, as depicted inFIG. 6C. From there, he lowers his arms 604 to shoulder level, asdepicted in FIG. 6D, and then again raises them up, to the approximatelevel of his head, as depicted in FIG. 6E. Where a system captures thesepositions by the user 602 without any intervening position that maysignal that the gesture is cancelled, or another gesture is being made,it may recognize the fair catch gesture as having been made by the user602.

FIG. 7 depicts the example “fair catch” gesture of FIG. 5 as each frameof image data has been parsed to produce a skeletal map of the user. Thesystem, having produced a skeletal map from the depth image of the user,may now determine how that user's body moves over time, and from that,parse the gesture.

In FIG. 7A, the user's shoulders 310, are above his elbows 306, which inturn are above his hands 302. The shoulders 310, elbows 306 and hands302 are then at a uniform level in FIG. 7B. The system then detects inFIG. 7C that the hands 302 are above the elbows, which are above theshoulders 3 10. In FIG. 7D, the user has returned to the position ofFIG. 7B, where the shoulders 310, elbows 306 and hands 302 are at auniform level. In the final position of the gesture, shown in FIG. 7E,the user returns to the position of FIG. 7C, where the hands 302 areabove the elbows, which are above the shoulders 310.

While the depth camera 402 captures a series of still images, such thatin any one image the user appears to be stationary, the user is movingin the course of performing this gesture (as opposed to a stationarygesture, as discussed supra). The system is able to take this series ofposes in each still image, and from that determine the moving gesturethat the user is making.

In performing the gesture, a user is unlikely to be able to create anangle as formed by his right shoulder 310 a, right elbow 306 a and righthand 302 a of, for example, between 140° and 145°. So, the applicationusing the filter 418 for the fair catch gesture 428 may tune theassociated parameters 426 to best serve the specifics of theapplication. For instance, the positions in FIGS. 7C and 7E may berecognized any time the user has his hands 302 above his shoulders 310,without regard to elbow 306 position. A set of parameters that arestricter may require that the hands 302 be above the head 310 and thatthe elbows 306 be both above the shoulders 310 and between the head 322and the hands 302. Additionally, the parameters 426 for a fair catchgesture 428 may require that the user move from the position of FIG. 7Athrough the position of FIG. 7E within a specified period of time, suchas 1.5 seconds, and if the user takes more than 1.5 seconds to movethrough these positions, it will not be recognized as the fair catch418.

FIG. 8 depicts how generic gesture filters 806 from a gesture filterlibrary 802 are grouped into genre packages 804 of complementary gesturefilters for a particular task. The gesture filter library 802 aggregatesall gesture filters 806 provided by the system. In an embodiment, anapplication may provide additional gesture filters for thatapplication's use. Generic gesture filters comprise things such as “armthrow” 806 a and “crouch down” 806 b. These gesture filters are thengrouped together in genre packages 804.

A genre package 804 may include those gestures that are commonly usedwithin a genre. For instance, a first-person shooter (FPS) genre package804 a may have gesture filters for shooting a weapon 812 c, throwing aprojectile 812 d, punching 812 e, opening a door 812 f, crouching 812 g,jumping 812 h, running 812 i, and turning 812 j. This FPS genre package804 a may be thought of as providing a generic FPS genre package 808a—one with gesture filter parameters tuned or set so that they willlikely work acceptably with a large number of FPS applications.

A genre package is not limited to groups of complementary gesturefilters that work for known genres or applications. A genre package maycomprise gesture filters that comprise a subset of those filters used byan application or genre, or filters that are complementary, though anappropriate genre for them has yet to be identified.

An application may then tune those generic genre packages to meet theparticulars of that application. The application may tune a genericgenre package by setting values for parameters of filters in the genrepackage. For instance, the creators of Game A 810 a may decide thattheir game functions best when a demonstrative movement is required toregister the opening a door gesture filter 812 f, because otherwise itis too similar to the punching gesture filter 812 e. However, thecreators of Game B may decide that this is not a concern, and requireonly a more modest movement to register the opening a door gesturefilter 812 fB.

In the embodiment where a genre package comprises machine-readableinstructions, a genre package may be provided as those instructions insource code form, or in a form reflecting some amount of compilation ofthose instructions.

FIG. 9 illustrates exemplary operational procedures for tuningcomplementary gesture filters in a filter package when an applicationprovides a value for one parameter of one filter.

Operation 902 depicts providing a package comprising a plurality offilters, each filter comprising information about a gesture and at leastone parameter, each filter being complementary with at least one otherfilter in the package. The package may represent gesture filters for aparticular genre. For example, genre packages for video games mayinclude genres such as first-person shooter, action, driving, andsports.

As used herein, and in at least one embodiment, “providing a package”may refer to allowing access to a programming language library file thatcorresponds to the filters in the package or allowing access to anapplication programming interface (API) to an application. The developerof the application may load the library file and then make method callsas appropriate. For instance, with a sports package there may be acorresponding sports package library file.

When included in the application, the application may then make callsthat use the sports package according to the given API. Such API callsmay include returning the value of a parameter for a filter, setting thevalue of a parameter for a filter, and correlating identification of afilter with triggering some part of the application, such as causing auser controlled tennis player to swing a tennis racket when the usermakes the appropriate tennis racket swing gesture.

As described above, a gesture may comprise a wide variety of things. Itmay, for instance, be any of a crouch, a jump, a lean, an arm throw, atoss, a swing, a dodge, a kick, and a block. Likewise, a gesture maycorrespond to navigation of a user interface. For instance, a user mayhold his hand with the fingers pointing up and the palm facing the 3Dcamera. He may then close his fingers towards the palm to make a first,and this could be a gesture that indicates that the focused window in awindow-based user-interface computing environment should be closed.

As gestures may be used to indicate anything from that an avatar in anapplication should throw a punch to that a window in an applicationshould be closed, a wide variety of applications, from video games totext editors may utilize gestures.

Complementary gesture filters—either complementary as in those that arecommonly used together, or complementary as in a change in a parameterof one will change a parameter of another—may be grouped together intogenre packages that are likely to be used by an application in thatgenre. These packages may be available or identified to an application,which may select at least one. The application may tune, or modify, theparameter(s) of a filter in a selected package to best fit the uniqueaspects of the application. When that parameter is tuned, a second,complementary parameter (in the inter-dependent sense) of either thefilter or a second filter may also be tuned such that the parametersremain complementary.

The application-determined parameter may vary based on the context theapplication is in. To that end, an application may assign a plurality ofvalues to an application-determined parameter for a filter, each valuecorresponding to a different context. As discussed supra, this contextmay be a cultural context or an environmental context.

Operation 904 depicts receiving an indication of assigning a value to aparameter of a first filter. An application-determined parameter maycomprise any of a wide variety of characteristics of a filter, such as abody part, a volume of space, a velocity, a direction of movement, anangle, and a place where a movement occurs.

In an embodiment, the value of the application-determined parameter isdetermined by an end user of the application through making a gesture.For instance, an application may allow the user to train it, so that theuser is able to specify what motions he believes a gesture shouldcomprise. This may be beneficial to allow a user without good controlover his motor skills to be able to link what motions he can make with acorresponding gesture. If this were not available, the user may becomefrustrated because he is unable to make his body move in the mannerrequired by the application to produce the gesture.

In an embodiment where there exist complementary filters—a plurality offilters that have inter-related parameters—receiving from theapplication a value for an application-determined parameter of the firstfilter may include both setting the application-determined parameter ofthe first filter with the value, and setting a complementaryapplication-determined parameter of a second, complementary filter basedon the value of the parameter of the first filter. For example, one maydecide that a user who throws a football in a certain manner is likelyto also throw a baseball in a certain manner. So, where it is determinedthat a certain application-determined parameter of one filter, such as avelocity parameter on a filter for a football throw gesture, should beset in a particular manner, other complementary application-determinedparameters, such as the velocity parameter on a baseball throw gesture,may be set based on how that first application-determined parameter isset.

This need not be the same value for a given application-determinedparameter, or even the same type of application-determined parameteracross filters. For instance, it could be that when a football throwmust be made with a forward arm velocity of X m/s, then a football catchmust be made with the hands at least distance Y m away from the torso.

The value may be a threshold, such as arm velocity is greater than X. Itmay be an absolute, such as arm velocity equals X. There may be a faulttolerance, such as arm velocity equals within Y of X. It may alsocomprise a range, such as arm velocity is greater than or equal to X,but less than Z.

Operation 906 depicts assigning the value to the parameter of the firstfilter. Where an association between parameters and their values isstored in a database, this may comprise storing the value in thedatabase along with an association with the parameter.

Operation 908 depicts assigning a second value to a second parameter ofa second filter, the second value determined using the value assigned tothe parameter of the first filter. As discussed above, the second valuemay relate to the first value in a variety of ways. Where the twoparameters involve something substantially similar such as a thresholdjump height, the second value may be equal to the first value. Thesecond value and the first value may have a variety of otherrelationships, such as a proportional relationship, an inverselyproportional relationship, a linear relationship, an exponentialrelationship, and a function that takes the value as an input.

In an embodiment where filters may inherit characteristics from eachother, such as in an object-oriented implementation, the second filtermay comprise a child of the first filter, with the first filter likewisebeing a parent to the second filter. Take for example, a “hand slap”filter. This filter may serve as a parent to variations on hand slaps,such as the “high five,” the “high ten” and the “low five.” Where the“hand slap” has a “hand movement distance threshold” parameter, when thevalue to that parameter is set, the “hand movement distance threshold”parameter for all child filters may be set with that same value.

Likewise, the complementary nature of two parameters may be due to onefilter being stacked to be incorporated into another filter. One filtermay be a steering filter, and that is stacked with other filters such asgear shift, accelerate and decelerate to create a driving filter. As the“minimum steering angle threshold” parameter of the steering filter ismodified, the corresponding “minimum steering angle threshold” parameterof the driving filter may also be modified.

Operation 910 depicts the optional operation of receiving datacomprising an image of a person, and when parsing filters to determineif the data matches a particular filter (and thus indicates a particulargesture), parsing the data for each filter in a selected package beforeparsing the data for a filter not in the package. Where an applicationselects a filter package for use, such as by including a library filefor that filter package, it likely does so because those filters are tobe frequently used by a user of the application. Further, filters in afilter package may be used in close succession, such as with run, jump,strafe, crouch and discharge firearm filters in a first-person shooterpackage. To this end, where a filter package has been identified asbeing used by an application, a system processing filters, such as thebase filter engine described above, can likely reduce the processingresources required to process image data corresponding to user input byfirst processing the data for those filters comprising the selectedfilter package.

Operation 912 depicts the optional operation of receiving an indicationof assigning a third value to the second parameter, and assigning thethird value to the second parameter. A relationship between twoparameters need not be bilateral. It may be that a change in the valueaffects the second value, but that a change in the second value does notaffect the first value.

Operation 914 depicts the optional operation of assigning a fourth valueto the parameter, the fourth value determined using the third value. Itmay also be that the relationship between the two parameters arebilateral. In this embodiment, a change in a value of the secondparameter results in changing a value of the first parameter, asdetermined using the new value of the second parameter.

Operation 916 depicts the optional operation of receiving datacomprising an image of a person; determining that the data matches thefirst filter of the package; and parsing the data for each other filterin the package that can be indicated by the user simultaneously with thefirst filter before parsing the data for a filter that cannot beindicated by the user simultaneously with the filter. In an embodiment,filters in a filter package may be used simultaneously, such as asimultaneous run filter and discharge firearm filter in a first-personshooter package. To this end, where a filter package has been identifiedas being used by an application, a system processing filters, such asthe base recognizer engine discussed above, can likely reduce theprocessing resources required to process image data corresponding touser input by first processing the data for those filters comprising thefilter package.

Conclusion

While the present disclosure has been described in connection with thepreferred aspects, as illustrated in the various figures, it isunderstood that other similar aspects may be used or modifications andadditions may be made to the described aspects for performing the samefunction of the present disclosure without deviating there from.Therefore, the present disclosure should not be limited to any singleaspect, but rather construed in breadth and scope in accordance with theappended claims. For example, the various procedures described hereinmay be implemented with hardware or software, or a combination of both.Thus, the methods and apparatus of the disclosed embodiments, or certainaspects or portions thereof, may take the form of program code (i.e.,instructions) embodied in tangible media, such as floppy diskettes,CD-ROMs, hard drives, or any other machine-readable storage medium. Whenthe program code is loaded into and executed by a machine, such as acomputer, the machine becomes an apparatus configured for practicing thedisclosed embodiments. In addition to the specific implementationsexplicitly set forth herein, other aspects and implementations will beapparent to those skilled in the art from consideration of thespecification disclosed herein. It is intended that the specificationand illustrated implementations be considered as examples only.

1. A method for providing a package of complementary gesture filters toan application, comprising: providing a package comprising a pluralityof filters, each filter comprising information about a gesture, at leastone filter being complementary with at least one other filter in thepackage; receiving an indication of assigning a first value to aparameter of a first filter; assigning the value to the parameter; andassigning a second value to a second parameter of a second filter, thesecond value determined using the first value.
 2. The method of claim 1,wherein the parameter of the first filter represents a body part, avolume of space, a velocity, a direction of movement, an angle, atwo-dimensional (2D) plane, or a place where a movement occurs.
 3. Themethod of claim 1, wherein the gesture comprises a crouch, a jump, alean, an arm throw, a toss, a swing, a dodge, a kick, or a block.
 4. Themethod of claim 1, wherein a filter is complementary with at least oneother filter in the package when (i) that filter has at least oneparameter that is determined based on a parameter of the at least oneother filter in the package, (ii) that filter represents a gesture thatis commonly made by a user within a short time period of a gesturerepresented by the at least one other filter in the package, or (iii)the gesture represented by that filter is capable of being madesimultaneously with a gesture represented by the at least one otherfilter in the package.
 5. The method of claim 1, wherein the indicationof assigning the value to the parameter is received as a result of theuser making the gesture.
 6. The method of claim 1, wherein the value isa fixed value, a range, or a value with a tolerance.
 7. The method ofclaim 1, wherein the second value is determined using the first valuebased on a proportional relationship, an inversely proportionalrelationship, a linear relationship, an exponential relationship, or afunction that takes the first value as an input.
 8. The method of claim1, wherein the package contains complementary gesture filters for aparticular genre, and wherein the genre is one of a first-personshooter, action, driving, or sports genre.
 9. The method of claim 1,wherein the application is a video game or an operating system.
 10. Themethod of claim 1, further comprising: receiving an indication ofassigning a third value to the second parameter; and assigning the thirdvalue to the second parameter.
 11. The method of claim 10, furthercomprising: assigning a fourth value to the first parameter, the fourthvalue determined using the third value.
 12. The method of claim 1,wherein the indication of assigning the first value to the parameter ofthe first filter is received from the application.
 13. The method ofclaim 1, wherein the indication of assigning the first value to theparameter of the first filter is received as a result of a context ofthe application being changed.
 14. The method of claim 1, wherein thesecond filter comprises a child of the first filter.
 15. The method ofclaim 1, wherein the second filter is a stacked filter comprising thefirst filter.
 16. A system for providing a package of complementaryfilters to an application, comprising: a filter library comprising atleast one package of filters, each filter comprising information about agesture, at least one filter of the at least one package beingcomplementary with at least one other filter in the package; andcircuitry that provides a filter package to the application, receivesdata corresponding to at least one image of at least part of a user,determines that the data corresponds to at least two matched filters,determines how a first filter of the matched filters operates with atleast one other filter of the matched filters, and sends an outputcorresponding to each matched filter to the application.
 17. The systemof claim 16, wherein the output comprises a confidence level, and thecircuitry determines how a first matched filter operates with at leastone other matched filter by altering the confidence level of the firstfilter based on the confidence level of the at least one other matchedfilter.
 18. The system of claim 16, wherein the circuitry further:parses the data for each filter in the package to determine if the dataindicates a match with one or more of the filters of the package, beforeparsing the data for a filter not in the package.
 19. The system ofclaim 16, wherein the circuitry further: parses the data for each otherfilter in the package that can be parsed simultaneously with the atleast one filter that corresponds to the data before parsing the datafor a filter that cannot be parsed simultaneously with the at least onefilter that corresponds to the data
 20. A computer readable storagemedium, comprising computer readable instructions that when executed ona processor, cause the processor to perform the operations of: providinga package comprising a plurality of filters, each filter comprisinginformation about a gesture, each filter being complementary with atleast one other filter in the package, a gesture being input by a usermaking a motion or pose associated with that gesture that is captured bya distance camera; receiving an indication of assigning a first value toa parameter of a first filter; assigning the value to the parameter; andassigning a second value to a second parameter of a second filter, thesecond value determined using the first value.